Signaling buffer parameters indicative of receiver buffer architecture

ABSTRACT

The specification and drawings present a new method, system, apparatus and software product for signaling parameters of multiple buffers by a terminal to a server and determining multiple buffer status of the terminal by the server using these parameters, e.g., for an adequate rate adaptation of multimedia streaming services provided to the terminal by the server. The terminal can be (but is not limited to) a computer, a communication device, a wireless communication device, a portable electronic device, a mobile electronic device, a mobile phone, etc.

PRIORITY AND CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from U.S. Provisional Patent Application Ser. No. 60/649,995 filed on Feb. 3, 2005.

FIELD OF THE INVENTION

This invention relates to multimedia communications and more specifically to signaling buffer parameters indicative of receiver buffer status.

BACKGROUND ART

During the DLNA (Digital Living Network Alliance) RTP-TF (Real Time Protocol-Task Force) F2F (Face to Face) meeting on Jan. 26, 2005, problems were identified when discussing the schemes for bit rate adaptation. The conclusion was that different receiver buffer models might need to be considered in order for the receiver buffer feedback to be meaningful for the sender, and to enable the sender to perform an efficient adaptation.

The prior art on this topic is given, for example, in regard to the rate adaptation scheme specified for streaming in 3GPP (3d Generation Partnership Project) and 3GPP2 (3d Generation Partnership Project 2) specifications as described in Technical Specification 26.234 v.6.2.0 “Transparent End-to-end Packet Switched Streaming Service (PSS) Protocols and Codecs”, and in Technical Specification C.P0046 v.0.1.7, “3G Multimedia Streaming Services”.

The current buffer model defined in 3GPP/3GPP2 is a single buffer, and it contains an RTP (real time protocol) header and a payload. In order to support different buffer models, (e.g., containing more than one buffer) the current prior art signaling schemes are not sufficient to guarantee a workable and efficient solution, e.g., for the adequate rate adaptation.

FIGS. 1-3 show various buffer architectures which can be employed, according to the prior art.

DISCLOSURE OF THE INVENTION

A new method, system, apparatus and software product are presented for signaling parameters for multiple buffers by a terminal to a server and determining multiple buffer status of the terminal by the server using these parameters, e.g., for an adequate rate adaptation of multimedia streaming services provided to the terminal by the server.

According to a first aspect of the invention, a method for signaling buffer parameters, comprises the steps of: sending buffer parameters from a terminal to a server, wherein the buffer parameters relates to at least two buffers of N terminal, and N is an integer of at least a value of two; receiving the buffer parameters from the terminal at the server; and determining a status of the at least two buffers by the server using the buffer parameters.

According further to the first aspect of the invention, the buffer parameters may comprise at least one of: a) a number of the at least two buffers; b) buffer sizes of the at least two buffers; c) buffer size units of the at least two buffers; d) a partial header size in the at least two buffers; e) and a buffer transfer mechanism index, for indicating a transfer mechanism between the at least two buffers. Further, the buffer parameters may further comprise a playout delay unit, for modifying a timing unit.

Further according to the first aspect of the invention, the buffer parameters may comprise: a video pre-decoder buffer indicator; and a video post-decoder buffer indicator.

Still further according to the first aspect of the invention, the at least two buffers may be out of: a) a de-jitter buffer; b) a pre-decoder buffer; and c) a post-decoder buffer.

According further to the first aspect of the invention, the at least two buffers may comprise all N terminal buffers.

According to a second aspect of the invention, a computer program product comprises: a computer readable storage structure embodying computer program code thereon for execution by a computer processor with the computer program code characterized in that it includes instructions for performing the steps of the first aspect of the invention, indicated as being performed by any component or a combination of components of the terminal or the server.

According to a third aspect of the invention, a communication system, comprises of: a terminal, for providing and sending buffer parameters, wherein the buffer parameters relate to at least two buffers of N terminal buffers of the terminal, wherein N is an integer of at least a value of two; and a server, for receiving the buffer parameters from the terminal and for determining a status of the at least two buffers using the buffer parameters.

According further to the third aspect of the invention, the buffer parameters may comprise at least one of: a) a number of the at least two buffers; b) buffer sizes of the at least two buffers; c) buffer size units of the at least two buffers; d) a partial header size in the at least two buffers; and e) a buffer transfer mechanism index, for indicating a transfer mechanism between the at least two buffers. Further, the buffer parameters may further comprise a playout delay unit, for modifying a timing unit.

According further to the third aspect of the invention, the buffer parameters may comprise: a video pre-decoder buffer indicator; and a video post-decoder buffer indicator.

Further according to the third aspect of the invention, at least two buffers may be out of: a) a de-jitter buffer; b) a pre-decoder buffer; and c) a post-decoder buffer.

Still further according to the third aspect of the invention, the at least two buffers may comprise all N terminal buffers.

According to a fourth aspect of the invention, a terminal, comprises: N terminal buffers, wherein N is an integer of at least a value of two; a terminal control block for providing buffer parameters related to at least two buffers of the N terminal buffers; and input/output terminal block, for sending the buffer parameters from the terminal to a server, for determining a status of the at least two buffers by the server using the buffer parameters.

According further to the fourth aspect of the invention, the terminal may be a computer, a communication device, a wireless communication device, a portable electronic device, a mobile electronic device or a mobile phone.

Further according to the fourth aspect of the invention, the input/output terminal block and the input/output terminal block may be combined.

According to a fifth aspect of the invention, a server, comprises: an input/output block for receiving buffer parameters from a terminal, wherein the buffer parameters relates to at least two buffers of N terminal buffers of the terminal, wherein N is an integer of at least a value of two; and a server control block for determining a status of the at least two buffers using the buffer parameters.

According further to the fifth aspect of the invention, the server control block may adapt a transmission rate according to the status and using a predetermined criterion, and wherein the input/output block sends media content from the server to the terminal using the adapted transmission rate.

Advantages of the invention include but are not limited to the following:

-   -   The receiver uses the signaling to inform the buffer parameters         to the sender, so the sender can better understand the receiver         buffer status; and     -   The signaling allows the buffer feedback information to be         scalable.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the nature and objects of the present invention, reference is made to the following detailed description taken in conjunction with the following drawings, in which:

FIGS. 1-3 are schematic diagrams showing various possible receiver buffer architectures, according to the prior art;

FIG. 4 is a block diagram illustrating signaling buffer parameters indicative of the buffer architecture sent from a receiver (terminal) to a sender (server), according to an embodiment of the present invention; and

FIG. 5 is a flow chart illustrating signaling buffer parameters indicative of the buffer architecture sent from a receiver (terminal) to a sender (server), according to an embodiment of the present invention.

MODES FOR CARRYING OUT THE INVENTION

A new method, system, apparatus and software product are presented for signaling parameters of multiple buffers by a terminal to a server and determining multiple buffer status of the terminal by the server using these parameters, e.g., for an adequate rate adaptation of multimedia streaming services provided to the terminal by the server. The terminal can be (but is not limited to) a computer, a communication device, a wireless communication device, a portable electronic device, a mobile electronic device, a mobile phone, etc.

According to an embodiment of the present invention, when a multimedia streaming receiver (e.g., a DMP client, as defined in DLNA) is connected to the sender (e.g., a DMS (DEKSI Modem Pooling) server as defined in the DLNA), the receiver sends at least one of the following buffer parameters (or the multiple buffer parameters) indicative of, but not limited to, a number of buffers (e.g., a jitter buffer, a pre-decoder buffer, a post-decoder buffer, etc.), buffer sizes, buffer size units, a partial header size (e.g., part of the RTP header, see IETF RFC 3550, “RTP: A Transport Protocol for Real-time applications,” July 2003), and the transfer mechanism between the two buffers. Moreover, according to a further embodiment of the present invention, the receiver also sends the time unit for the playout delay as defined in Technical Specification 26.234 v.6.2.0 “Transparent End-to-end Packet Switched Streaming Service (PSS) Protocols and Codecs”.

The current buffer model defined in 3GPP/3GPP2 is a single buffer, and it contains an RTP (real time protocol) header and a payload. If a two-buffer model is used, in which the receiver exposes to the server at least two buffers instead of one (for example, the jitter buffer and the pre-decoder buffer), and the management mechanism of the two buffers is unknown to the sender, then the receiver buffer signaling currently defined in 3GPP and 3GPP2 will be meaningless. By informing the buffer parameters from receiver to the sender according to embodiments of the present invention, the sender can deduct the correct receiver's buffer status, e.g., for the proper rate adaptation.

According to an embodiment of the present invention, the buffer parameters can, for instance, be defined (but not limited to) as follows:

-   -   Number of buffers, i.e., to indicate the number of receiver         buffers;     -   Buffer sizes, i.e., a number of blocks for each of the buffers;     -   Buffer size units, i.e., the block sizes for the buffers. The         current 3GPP FBS (Free Buffer Space) field (e.g., see Technical         Specification 26.234 v.6.2.0 “Transparent End-to-end Packet         Switched Streaming Service (PSS) Protocols and Codecs”) defines         a block comprising 64 bytes; this parameter (i.e., the FBS         field) can modify the unit indicating that each block indicates         any arbitrary number of bytes (for example, a block can be         defined in units of 128 bytes);     -   A partial header size, i.e., the partial RTP (real time         protocol) header size in the buffers;     -   Data transfer mechanism (or buffer transfer mechanism) index:         the index indicates what kind of transfer mechanism is used         between the buffers;     -   Playout delay unit, i.e., the playout delay timing unit; the         current 3GPP playout delay is defined in ms; this signal is used         to modify the timing unit, etc.

According to a further embodiment of the present invention, the signaling can be carried using a protocol out of a plurality of protocols which can be (but are not limited to) RTSP (real time streaming protocol), SDP (session description protocol), XML (extensible markup language), RTCP (real time conferencing protocol), e.g., APP (application) packet or RTP/AVPF (audio visual profile feedback), etc.

Alternatively, according to a further embodiment of the present invention, implicit assumptions on the relations of the buffers can be made and some of the parameters above can therefore be combined. For example, the buffer parameters may include the following binary indicators:

-   -   Video pre-decoder buffer indicator:         -   a) when the pre-decoder buffer indicator is 1, the receiver             contains a video pre-decoder buffer which operates             identically to the coded picture buffer (CPB) in the             Hypothetical Reference Decoder (HRD) of the video coding             standard in use;         -   b) when the pre-decoder buffer indicator is 0, a video             pre-decoder buffer is not present (i.e., it is combined with             de-jittering buffer) or the operation of the pre-decoder             buffer is unspecified; and     -   Video post-decoder buffer indicator:         -   a) when the post-decoder buffer indicator is 1, the receiver             contains a video post-decoder buffer which operates             identically to the decoded picture buffer (DPB) in the             Hypothetical Reference Decoder (HRD) of the video coding             standard in use; if there is no DPB specified in the HRD,             then the receiver contains a minimum reordering buffer             specified as follows: the minimum reordering buffer is             non-existing if the decoding order of pictures is the same             as their output order, or the minimum reorder buffer holds             one picture if B pictures according to MPEG (Moving Pictures             Experts Group) standards such as, e.g., MPEG-2, MPEG-4 Part             2, or according to standards H.263 are present in the             received stream;         -   b) when the post-decoder buffer indicator is 0, the presence             and operation of post-decoder buffer in unspecified.

When these binary indicators are present, then it is assumed that the indicated size of the buffer covers reception, de-jittering, and, if used, de-interleaving buffer(s) and has this given amount of space for complete application data units (ADU), including the following RTP header and RTP payload header fields. Any pre-decoder buffer which cannot be used as a de-jitter, a de-interleaving, or a retransmission buffer is not included in the indicated buffer size. When the binary indicators are equal to 1, then the size of the pre-decoder and/or post-decoder buffers is determined by the video coding profile and level in use.

Below is one illustrating example, according to the embodiments of the present invention, using the RTSP (real time streaming protocol) for two buffers with the following parameters:

-   -   url=“rtsp://server.example.corn/media.mp4”;     -   NB=2;     -   BF1 (1^(st) buffer size)=5000;     -   BSU1 (1^(st) buffer size unit)=1024;     -   BF2 (2^(nd) buffer size)=800;     -   BSU2 (2^(nd) buffer size unit)==512;     -   PHS (partial header size)=12;     -   BTM (buffer transfer mechanism) =0; and

PDU (playout delay unit)=10. Buffer # Buffer Size Buffer Unit Partial Header (NB) (BF, block) (BSU, byte) (PHS, byte) 1 5000 1024 0 2 800 512 12

The first buffer size is 5000*1024 bytes and the second buffer size is 800*512 bytes. The first buffer contains the full RTP header and payload so the partial header size is not signaled. The second buffer contains 12 bytes of partial headers. The partial RTP header size is important when Interleaved Packetization in H.264 RTP payload (see IETF RFC 3984, “RTP payload format for H.264 video, January 2005) is used.

The buffer size unit can, for example, be expressed by only few bits. If the value is 0, then 64-byte buffer blocks are used. If the value is 1 then 128-byte buffer blocks are used. If the value is 2, then 256-byte buffer blocks are used, and so on.

The buffer transfer mechanism (BTM) can be defined as follows:

-   -   0: when the second buffer has empty space then the first buffer         (e.g., the de-jitter) will transfer the data immediately;     -   1: the data is transferred according to packet's timestamp.     -   2: the data is transferred according to frame rate; for example,         video can be 30fps and audio can be 50fps;     -   3: The data is transferred to the second buffer only when the         first buffer is full;     -   4: other transfer mechanism than the above.

The above definition of the BTM represents only one example and other BTM definitions using different number of options are also possible.

The playout delay unit (PDU) modifier in the above example is 10x, which means the time unit is now 10 ms. For example, if the playout delay is 200 ms originally, then the new value is 2000 ms. Another example would be just to use one bit. If the bit is 1 the unit is expressed in 1/100^(th) of a second. If the bit is 0, then the unit is expressed in milliseconds.

It is noted that, according to an embodiment of the present invention, the multiple buffer parameters can relate to at least two buffers out of N terminal buffers, wherein N is an integer of at least a value of two. Further, the at least two buffers can comprise all N terminal buffers or selected buffers out of the N terminal buffers.

FIG. 4 shows an example among others of a block diagram illustrating signaling buffer parameters indicative of the buffer architecture sent from a receiver (terminal) 12 to a sender (server) 14 in a communication system 11, according to the embodiment of the present invention. The terminal 12 is called a receiver for purposes of the present invention because it is the recipient of a media (content) signal 22 comprising, e.g., multimedia services from the server 14. The receiver/terminal 12 has N buffers 16-1, 16-2, . . . , 16-N1 connected to a terminal control block 18 which is in turn connected to an input/output terminal block 20. The server can be viewed as having a similar internal structure comprising an input/output server block 24, a server control block 26 and a server buffer block 28, at least for purposes of the present invention, as shown.

The terminal control block 18 in FIG. 4 provides the buffer parameters related to at least two buffers of the N terminal buffers (16-1, 16-2, . . . , 16-N), according to the embodiments of the present invention as described above, to the block 20, which sends the buffer parameters (signal 10) to the corresponding block 24 of the server 14. The buffer information is then forwarded to the server control block 26 of the server 14. The block 26 determines the status of the at least two buffers of the terminal 12 using the received buffer parameters. Based on the status, the server 14 (using the server control block 26) can adapt a transmission rate using a predetermined criterion and send the media content signal 22 using the adopted transmission rate from the server 14 (using the block 24) to the terminal 12.

According to an embodiment of present invention, the blocks 20, 18, 24, 26, 16-1, 16-2, . . . , 16-N and 28 can be implemented as a software, a hardware block or a combination thereof. Furthermore, each of the blocks 20, 18, 24, 26, 16-1, 16-2, . . . , 16-N and 28 can be implemented as a separate block or can be combined with any other standard block of the terminal 12 or the server 14, or it can be split into several blocks according to their functionality.

FIG. 5 shows a flow chart illustrating signaling buffer parameters indicative of the buffer architecture sent from the receiver (terminal) 12 to the sender (server) 14 in a communication system 11, according to an embodiment of the present invention.

The flow chart of FIG. 5 only represents one possible scenario among others. In a method according to the first embodiment of the present invention, in a first step 40, the terminal 12 generates the buffer parameters of the at least two buffers according to the embodiments of the present invention, and sends these parameters (the signal 10) to the server 14. In a next step 42, the server 14 receives the buffer parameters from the terminal 12. In a next step 44, the server 14 determines the status of the at least two buffers using the buffer parameters. In a next step 46, the server 14 adapts a transmission rate according to the status and using the predetermined criterion. Finally, in a next step 48, the server 14 sends the media content (the signal 22) to the terminal 12 using the adapted transmission rate.

As explained above, the invention provides both a method and corresponding equipment consisting of various modules providing the functionality for performing the steps of the method. The modules may be implemented as hardware, or may be implemented as software or firmware for execution by a computer processor. In particular, in the case of firmware or software, the invention can be provided as a computer program product including a computer readable storage structure embodying computer program code (i.e., the software or firmware) thereon for execution by the computer processor.

It is to be understood that the above-described arrangements are only illustrative of the application of the principles of the present invention. Numerous modifications and alternative arrangements may be devised by those skilled in the art without departing from the scope of the present invention, and the appended claims are intended to cover such modifications and arrangements. 

1. Method for signaling buffer parameters, comprising the steps of: sending buffer parameters from a terminal to a server, wherein said buffer parameters relates to at least two buffers of N terminal buffers, and N is an integer of at least a value of two; receiving the buffer parameters from the terminal at the server; and determining a status of the at least two buffers by the server using the buffer parameters.
 2. The method of claim 1, wherein the buffer parameters comprise at least one of: a) a number of the at least two buffers; b) buffer sizes of the at least two buffers; c) buffer size units of the at least two buffers; d) a partial header size in the at least two buffers; and e) a buffer transfer mechanism index, for indicating a transfer mechanism between the at least two buffers.
 3. The method of claim 3, wherein the buffer parameters further comprise a playout delay unit, for modifying a timing unit.
 4. The method of claim 1, wherein the buffer parameters comprise: a video pre-decoder buffer indicator; and a video post-decoder buffer indicator.
 5. The method of claim 1, wherein the at least two buffers are out of: a) a de-jitter buffer; b) a pre-decoder buffer; and c) a post-decoder buffer.
 6. The method of claim 1, wherein the at least two buffers comprise all N terminal buffers.
 7. A computer program product comprising: a computer readable storage structure embodying computer program code thereon for execution by a computer processor with said computer program code characterized in that it includes instructions for performing the steps of the method of claim 1 indicated as being performed by any component or a combination of components of said terminal or the server.
 8. A communication system, comprising of: a terminal, for providing and sending buffer parameters, wherein said buffer parameters relate to at least two buffers of N terminal buffers of said terminal, wherein N is an integer of at least a value of two; and a server, for receiving the buffer parameters from the terminal and for determining a status of the at least two buffers using the buffer parameters.
 9. The system of claim 8, wherein the buffer parameters comprise at least one of: a) a number of the at least two buffers; b) buffer sizes of the at least two buffers; c) buffer size units of the at least two buffers; d) a partial header size in the at least two buffers; and e) a buffer transfer mechanism index, for indicating a transfer mechanism between the at least two buffers.
 10. The system of claim 9, wherein the buffer parameters further comprise a playout delay unit, for modifying a timing unit.
 11. The system of claim 8, wherein the buffer parameters comprise: a video pre-decoder buffer indicator; and a video post-decoder buffer indicator.
 12. The system of claim 8, wherein the at least two buffers are out of: a) a de-jitter buffer; b) a pre-decoder buffer; and c) a post-decoder buffer.
 13. The system of claim 8, wherein the at least two buffers comprise all N terminal buffers.
 14. A terminal, comprising: N terminal buffers, wherein N is an integer of at least a value of two; a terminal control block for providing buffer parameters related to at least two buffers of the N terminal buffers; and an input/output terminal block, for sending the buffer parameters from the terminal to a server, for determining a status of the at least two buffers by the server using the buffer parameters.
 15. The terminal of claim 14, wherein said terminal is a computer, a communication device, a wireless communication device, a portable electronic device, a mobile electronic device or a mobile phone.
 16. The terminal of claim 14, wherein the input/output terminal block and the input/output terminal block are combined.
 17. A server, comprising: an input/output block for receiving buffer parameters from a terminal, wherein said buffer parameters relates to at least two buffers of N terminal buffers of the terminal, wherein N is an integer of at least a value of two; and a server control block for determining a status of the at least two buffers using the buffer parameters.
 18. The server of claim 17, wherein the server control block adapts a transmission rate according to said status and using a predetermined criterion, and wherein the input/output block sends media content from the server to the terminal using said adapted transmission rate. 